com.github.timo_reymann.csv_parser.io.CsvWriter Maven / Gradle / Ivy
package com.github.timo_reymann.csv_parser.io;
import com.github.timo_reymann.csv_parser.meta.CsvMetaDataReader;
import com.github.timo_reymann.csv_parser.util.Converter;
import com.github.timo_reymann.csv_parser.util.Platform;
import lombok.Data;
import java.io.*;
import java.lang.reflect.Field;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.*;
/**
* Write csv files
*
* @author Timo Reymann
* @since 20.12.17
*/
@Data
public class CsvWriter implements AutoCloseable, Closeable, Flushable {
/**
* Append to file instead of replacing it completely
*/
private final boolean append;
/**
* File has csv headers
*/
private final boolean hasHeadings;
/**
* Class for bean
*/
private Class clazz;
/**
* Meta data provider for bean
*/
private CsvMetaDataReader csvMetaDataReader;
/**
* File to save
*/
private File file;
/**
* Seperator for lines
*/
private String seperator = Seperator.SEMICOLON;
/**
* File writer instance
*/
private FileWriter fileWriter;
/**
* Buffered Writer to write to file
*/
private BufferedWriter bufferedWriter;
/**
* Converter api
*/
private final Converter converter = new Converter();
/**
* Create new csv writer
*
* @param clazz Class for bean
* @param file File to write
* @param append Append to output
* @param hasHeadings Has the file headings, if this is a new file headers are automatically generated
* @param seperator Seperator for csv file
* @throws IOException Error opening file streams
*/
public CsvWriter(Class clazz, File file, boolean append, boolean hasHeadings, String seperator) throws IOException {
this.clazz = clazz;
this.file = file;
this.csvMetaDataReader = new CsvMetaDataReader<>(clazz);
this.append = append;
this.hasHeadings = hasHeadings;
this.seperator = seperator;
init();
}
/**
* Map beans to string array, this method automatically decides to map by heading or by index
*
* @param bean Bean to map
* @return String array with bean data mapped
* @throws IllegalAccessException Error getting values from bean
* @throws IOException Error writing header
*/
private String[] map(T bean) throws IllegalAccessException, IOException {
if (hasHeadings) {
return mapByHeading(bean);
}
return mapByIndex(bean);
}
/**
* Map bean by index
*
* @param bean Bean
* @return String array with data mapped according to specification over annotations
* @throws IllegalAccessException Error getting values from bean
*/
private String[] mapByIndex(T bean) throws IllegalAccessException {
HashMap effectiveMapping = csvMetaDataReader.getEffectiveValueForColumnMapping();
String[] data = new String[effectiveMapping.size()];
for (Map.Entry entry : effectiveMapping.entrySet()) {
data[(int) entry.getKey()] = formatValue(entry.getValue(), bean);
}
return data;
}
private String formatValue(Field field, Object obj) throws IllegalAccessException {
Object value = field.get(obj);
Class type = field.getType();
String format = csvMetaDataReader.getCsvColumnForField(field).format();
if (type.isAssignableFrom(LocalDateTime.class)) {
return converter.formatLocalDateTime(format, (LocalDateTime) value);
} else if (type.isAssignableFrom(LocalDate.class)) {
return converter.formatLocalDate(format, (LocalDate) value);
} else {
return value == null ? "" : value.toString();
}
}
/**
* Join list with strings to one single string separated by specified separator
*
* @param data List with strings to join
* @return String
*/
private String joinBySeperator(List data) {
return String.join(seperator, data);
}
/**
* Write file header then headings are used for mapping and no file exists or file is empty
*
* @param headings Headings
* @throws IOException Error writing header to file
*/
private void writeFileHeader(List headings) throws IOException {
if (file.length() > 0 || !hasHeadings)
return;
writeRawData(headings);
bufferedWriter.flush();
}
/**
* Write raw string array to file
*
* @param data Raw data
* @throws IOException Error writing to file
*/
private void writeRawData(List data) throws IOException {
bufferedWriter.write(joinBySeperator(data) + Platform.getLineSeperator());
}
private String[] mapByHeading(T bean) throws IllegalAccessException, IOException {
HashMap effectiveMapping = csvMetaDataReader.getEffectiveValueForColumnMapping();
List list = new ArrayList<>();
for (Map.Entry objectFieldEntry : effectiveMapping.entrySet()) {
Object key = objectFieldEntry.getKey();
list.add(key.toString());
}
writeFileHeader(list);
String[] data = new String[effectiveMapping.size()];
for (Map.Entry entry : effectiveMapping.entrySet()) {
int index = list.indexOf(entry.getKey().toString());
data[index] = formatValue(entry.getValue(), bean);
}
return data;
}
/**
* Write only file headings to file without any data
*
* @throws IllegalAccessException Error getting fields of entity
* @throws InstantiationException Error creating new instance of entity
* @throws IOException Error writing to file
*/
public void writeFileHeading() throws IllegalAccessException, InstantiationException, IOException {
if (isHasHeadings()) {
mapByHeading(clazz.newInstance());
}
}
/**
* Write bean to file
*
* @param bean Bean to write
* @throws IllegalAccessException Error getting value from object
* @throws IOException Error writing to file
*/
public void writeLine(T bean) throws IllegalAccessException, IOException {
writeRawData(Arrays.asList(map(bean)));
}
/**
* Write beans to file
*
* @param beans Beans to write
* @throws IllegalAccessException Error getting value from object
* @throws IOException Error writing to file
*/
public void writeLine(List beans) throws IOException, IllegalAccessException {
for (T bean : beans) {
writeLine(bean);
}
}
/**
* Init {@link BufferedWriter} and {@link FileWriter}
*
* @throws IOException Error open file
*/
private void init() throws IOException {
fileWriter = new FileWriter(file, append);
bufferedWriter = new BufferedWriter(fileWriter);
}
/**
* Flush underlying {@link BufferedWriter} and {@link FileWriter}
*
* @throws IOException Error flushing
*/
@Override
public void flush() throws IOException {
if (fileWriter != null)
fileWriter.flush();
if (bufferedWriter != null)
bufferedWriter.flush();
}
/**
* Close underyling {@link BufferedWriter} and {@link FileWriter}
*
* @throws IOException Error close writers
*/
@Override
public void close() throws IOException {
if (bufferedWriter != null)
bufferedWriter.close();
if (fileWriter != null)
fileWriter.close();
}
public static class Builder {
/**
* Append to file instead of replacing it completely
*/
private boolean append = true;
/**
* File has csv headers
*/
private boolean hasHeadings = false;
/**
* Class for bean
*/
private Class clazz;
/**
* File to save
*/
private File file;
/**
* Seperator for lines
*/
private String seperator = Seperator.SEMICOLON;
/**
* Set class of bean
*
* @param clazz Class object for bean
* @return Current builder
*/
public Builder forClass(Class clazz) {
this.clazz = clazz;
return this;
}
/**
* Set file to read from
*
* @param file CSV file
* @return Current builder
*/
public Builder file(File file) {
this.file = file;
return this;
}
/**
* Set seperator for csv reader, default it is set to ';'
*
* @param seperator Seperator
* @return Current builder
*/
public Builder seperatedBy(String seperator) {
this.seperator = seperator;
return this;
}
/**
* File to read has first row with heading
*
* @return Current builder
*/
public Builder hasHeading() {
this.hasHeadings = true;
return this;
}
public Builder noAppend() {
this.append = false;
return this;
}
public CsvWriter build() throws IOException {
return new CsvWriter<>(clazz, file, append, hasHeadings, seperator);
}
}
}